Each library sets its own opening hours, and each term or vacation can be different too. You can check opening hours for your library via the Libraries Directory.
Using the library out of hours
Some libraries allow swipe card or key access to the library outside of opening hours. This additional access may be available to all members of the college/department or just to postgraduates or members of staff. This access may have been arranged before you arrived, or you may need to have your card activated to provide this access. Your Librarian will be able to tell you what you need to do to get out-of-hours access to the library, if available.